Yesterday I saw this link about the "only 5 knots you will need." Not bad:
http://indefinitelywild.gizmodo.com/...ed-1696628878#
For me, I always go back to a bowline, clove hitch, prusik, Lark's head, two half-hitches, Trucker's hitch, tautline hitch, and midshipman's hitch (for various reasons, the three in bold are those that I use the most).
I keep a 2-ft section of parachord at my desk and review/practice each maybe once a month. I do the "big 3" with my eyes closed to simulate tying in darkness.